Circuit breaker having break-away walls



Feb. 13, 1968 A. R. NORDEN ETAL 3,369,099

CIRCUIT BREAKER HAVING BREAK-AWAY WALLS Original Filed Sept. 30, 1965 5Sheets-Sheet 1 Fig. 7

INVENTORS ALEXANDER'R. NORDEN HERMAN H- KOBRYNER r W I ATTORNEYS Feb.1968 A. R. NORDEN ETAL 3,369,099

CIRCUIT BREAKER HAVING BREAK-AWAY WALLS Original Filed Sept. 50, 1965 5Sheets-Sheet 2 Fig.4

INVENTORS ALEXANDER R. NO'RDBN HERMAN H- KOBRYNER 3Z2 2 ATTORNEYS- 5Sheets-Sheet 5 Feb. 13, 1968 A. R. NORDEN ETAL CIRCUIT BREAKER HAVINGBREAK AWAY WALLS Original Filed Sept. 30, 1965 Feb. 13, 1968 A. R.NORDEN ETAL CIRCUIT BREAKER HAVING BREAK-AWAY WALLS Original Filed Sept.30, 1965 5 Sheets-Sheet 4.

I \\M /4 II I 5 n 40 1/ /0 Y1 INVBNTORS ALEXANDER R.

ATTORNEYS A. R. NORDEN ETAL CIRCUIT BREAKER HAVING BREAK'AWAY WALLSOriginal Filed Sept. 30, 1965 Feb. 13, 1968 5 Sheets-$heet 5 INVENTORSALEXANDER R1 NORDEN HERMAN H. KOBRYNER ATTORNEYS United States PatentABSTRACT OF THE DISCLOSURE A two-pole circuit breaker is provided withspecifically located break-away Walls in order to afford alternativeaccess means for cable entry and attachment to the breaker lineconnectors.

This is a division of application Ser. No. 491,611, filed Sept. 30,1965, now Patent No. 3,339,052.

Th1s invention relates to circuit breakers and in particular to atwo-pole circuit breaker of the plug-in type for use in branch and maincircuits in a load center and as a service entrance breaker in anindividual enclosure. When mounting a circuit breaker in a load centeror lndrvidual enclosure, several considerations bear upon itspositioning. Where several breakers are mounted on a single panel board,the largest breaker dimension is generally disposed horizontally. (Forconvenience, we will refer to the breaker peripheral portion parallel tothe longest dimension as a side and the peripheral portion prependicularto this dimension as an end.) While there is no convention in such acase, it is desirable that all breaker operating handles assume the samerelative positlon for off and on. When used in a separate enclosure, onthe other hand, the breaker handle should be up for the on condition, asis the convention for all switches.

A distinct consideration is the relative disposition of the breakersvis-a-vis cable entrance openings, since it may be convenient to feedthe wires to the breaker either in line or perpendicular with thecircuit breaker side in order to reduce cable distortion.

Accordingly, it is the object of this invention to provlde a circuitbreaker designed in such a way that the same parts may be factoryassembled in different ways to produce breakers, adaptable to end orside wiring, with the handle on position in the first or second(opposite) direction. That is, four distinct alternatives are madeavailable:

(1) On-otf; side wiring.

(2) On-off; end wiring.

(3) Olf-on; side wiring.

(4) Off-on; end wiring.

It is another object of this invention to satisfy the first object insuch a manner that the factory produced breaker may be field modified tothe desired alternative.

The above mentioned and other features and objects of said invention andthe manner of attaining them will become more apparent, and theinvention itself will best be understood by reference to the followingdescription of an embodiment of the invention, taken in conjunction withthe accompanying drawings, wherein:

FIG. 1 is an outside side view of the illustrative twopole main circuitbreaker and is partially sectioned to show the manner in which cover andbase parts of the circuit breaker casing are secured to each other;

FIG. 2 is a top view of the circuit breaker;

3,369,999 Patented Feb. 13, 1968 ice FIG. 3 is a enlarged plan view ofthe circuit breaker, with the casing cover removed;

FIG. 4 is a sectional view taken substantially along line 44 of FIG. 3;

FIG. Sis a sectional view substantially along line 5-5 of FIG. 4 and isbroken away in part to show more clearly the form of a rockable bridgebetween the two poles of the circuit breaker;

FIG. 6 is a section taken substantially along lines 66 of FIG. 3;

FIG. 7 is a bottom view of the casing cover;

FIG. 8 is a fragmentary section on line 88 of FIG. 4;

FIG. 9 is an end view of a cam drum and its handle provided in thecircuit breaker for operating the switch means of the two poles of thecircuit breaker;

FIG. 10 is a fragmentary longitudinal sectional view through the basesection of an interior wall of the casing and shows a fulcruming notchin said base section for the bridge between the poles, a portion of thebridge and of a hold-down element therefor also being shown;

FIG. 11 is a detail fragmentary sectional view showing a modified formof a movable contact arm of the circuit breaker switch and also showinga modified connection between the arm and frame to permit side-swivelingof the arm;

FIG. 12 is a fragmentary front view of a modified contact provided onthe contact arm of FIG. 11 and shows this contact engaged along twodistinct contact surfaces with the fixed contact of the circuit breakerswitch; and

FIG. 13 is similar to FIG. 12 but shows the fixed contact as modified,instead of the movable contact, to provide two distinct contact surfacesfor engagement with the movable contact.

The illustrative circuit breaker is a two-pole circuit breaker, therespective poles of which comprise similar toggle-linked, magneticallytrippable switches. The two.

poles are housed alongside each other in an elongated insulating case 10(FIG. 1) made up of a cover part 10a (also see FIGS. 2 and 7) and a basepart-10b, fastened together by screws 11. The side and end walls, aswell as an interior longitudinal separating wall between the poles, arecomposed of matched sections of the cover and base.

Each pole includes a movable contact 13 for engaging a fixed contact 14.The fixed contacts of the respective poles are permanently secured onthe nose ends of a pair of copper bars 15 immovably set into the base 1%and separated by the wall 100. Bars 15 have coplanar straight sectionsover the floor of the base and are formed with elongated slots 15a, Onethrough each straight section, in parallel disposition, the slots beingspaced and sized so as to adapt them for plug-in engaged fit with a pairof bus blades of a suitable bus arrangement where each bus blade will beconnected with a bus for servicing a group of load circuits. Preferably,the slots 15a are spaced the standard distance of one inch prevailingfor bus blades of bus arrangements in load centers. The slotted portionsof bars 15 extend above access openings 16 centrally provided betweenthe ends of the base 10b. Flat insulating pieces 17 shield bars 15 atthe openings 16 except for the slots 15a which are exposed andaccessible for reception of a pair of bus blades. Fixed to bars 15 arethe legs of inverted U- shaped metal clips 18 (also see FIG. 8) whichare housed in pockets 19 of base 10b, each clip being above and inregistration with a slot 15a so as to provide increased contact pressurefor a bus blade.

The movable contacts 13 of the respective poles are permanently securedto the free ends of contact arms 13a which are elements of a pair ofupper assemblies insertably fitted side-by-side in the casing 10 andseparated by the interior casing wall 100. Common to and across bothassemblies is an insulating one-piece cam drum 20 integrally providedwith a handle 21 which projects from the middle section of the cam drumthrough an opening in the top of the casing. At opposite sides of itsmiddle section, the drum 20 is formed with a pair of identicalbifurcated or channeled cams 22, one for each pole assembly. Each poleassembly includes an L-frame having a side lug 24 (FIGS. 4 and 5) keyedinto a locating notch 25 (FIG. 7) in the side of the casing cover 10a.The vertical leg of the frame 23 terminates in a pair of yoke arms 26which straddle a cam 22 and carry a pivot pin 27 for the cam. The innerend of each pivot pin abuts the middle section of the drum 20, the outerend of the pin insertably fits into a notch 28 in the adjacent side ofthe cover 10a. The two pins 27, one to each side of the central sectionof the drum, thus journal the drum on the pair of frames 23. The pinsare free in the support arms 26 and in the drum and may he slipped outwhen the upper assemblies are out of the casing (for fieldmodification).

The drum 20 is formed at opposite ends with arcuate flanges 30 spacedaround the arcuate tops of the outer frame arms 26. Engagement of theends of the flanges with opposite side edges of these frame arms limitsthe angle through which the drum may be moved. This is the angle betweenand on positions of the drum and its handle 21, the angle being 90degrees in the present embodiment. Nested between each flange 30 and thetop of the adjacent frame arm 26 is a small coil spring 31 which ishooked at its upper end on a stud 32 projecting from the drum end. Thelower end of the spring may be hooked into either one of the oppositeholes 33 and 34 in the frame arm. In the attitude of the circuit breakershown in FIG. 4, the handle when in off position points away from thetail (load) end of the circuit breaker, the lower end of the spring 31is hooked into the hole 33 and the spring biases the drum and handlecounterclockwise. To set the handle 21 in on position, it will be movedto the right. It is anticipated that the manufacturer will offer leftand right handle positions as stock items and that the same parts willbe assembled differently to effect this result. Should fieldmodification be required, however, the upper pole assemblies may beremoved from the casing 10, the springs 31 unhooked from the holes 33,the pivot pins 27 removed, and the drum 20 dismounted. The drum is thenreversed end-around and remounted by re-inserting the pivot pins 27after which the lower ends of the spring 31 may be hooked into the holes34 in the outer arms 26. With the drum 20 re-assembled on the frames 23in end-around attitude relative to its attitude in FIG. 4, the handle inoff position will point towards the tail end of the circuit breaker andwill be biased by the springs 31 in that direction.

The cams 22 of the drum 20 and switch-operating linkages will have thesame working relation regardless of whether the drum is mounted in theattitude shown in FIG. 4 or in the end-around attitude, as will be madeclear. The switch-operating linkage of each pole is here a togglelinkage which includes a first link 35 and a second link 36 pivotallyconnected at its upper end to the first link by a pin 37 and pivoted'atits lower end by a pin 38 to the movable contact arm 13a of the pole. AU- shaped stiff wire latch 39 is pivotally carried by the second linkand engages the first link. The contact arm 13a is provided at its rearend with a slot 40a, extending generally in the direction of movement ofthe contact arm, for receiving a pin 40 (see FIGS. 4 and 6) supportedbetween lower ears 41 of a frame 23, whereby the contact arm isfloatingly pivoted to the frame. A looped Wire spring 42 engaged withthe contact arm provides restoring force for the arm and the connectedlinkage.

The upper end of first link 35 (FIGS. 4 and of each toggle intrudes intothe channel of a cam 22 so as to be restricted in side play. Directlybelow the channel, the link 35 ro-tatively carries a follower pin 43engaging the cam sections partially divided by the channel. The ends ofthe pin 143 are slidably guided in straight slots 44 (also see FIG. 6)formed in the pair of frame arms 26 which straddle the cam. A wirespring 45 presses the follower pin against the cam periphery. The guideslots 43 are disposed along a radial line (vertical, as shown) whichbisects the off to on angle degrees) of the drum 20 and its handle 21.FIG. 9 shows the cam profile and the relation thereto of the camfollower pin 43 when the drum is in ofi" position. The follower pin isthen in the crotch between an abrupt, vertical edge 22a of the camprofile and the low end of a curved cam rise 22b which terminates in adepression 22c. If the handle 21 now be moved (clockwise in FIG. 9) toits on position, the cam rise will traverse the follower pin and actuateit downwardly in the guide slots 44 until depression 22c of the camseats on the pin, which occurs at the end of the 90- degree movement ofthe handle when the handle reaches on" position.

It is clear now that since the ofF' and on positions of the drum 20 aresymmetrical with respect to the locus of travel of the follower pin 43,the drum 20 may be turned around on the frames 23, end-to-end, in themanner previously explained, without changing the working relation ofthe cam to the follower pin, so that the off and on positions of thehandle 21 may be interchanged to suit convention in any attitude of thecircuit breaker in the load center.

When the handle 21 is moved to on position, the cams 22 act on followerpins 43 to drive the toggles of both poles to lowered, latched positionin which the contacts 13 on contact arms 13a engage the fixed contacts14. Manual return of the handle to off position permits the springs 42to restore the toggles to raised position in which the contacts 13 aredisengaged from contacts 14.

Either toggle may be tripped from lower, latched position by rocking itslatch 39 forwardly, the latch being the equivalent of the toggle latchshown in Patent 2,759,063. For this purpose, each pole includes a knownform of electromagnetic means responsive to an overload current in thepole circuit. The electromagnetic means comprises a core unit 50, fixedon the horizontal leg of the frame 23, and a winding 51 in the currentconducting circuit of the pole. When the current exceeds the rating, theelectromagnet develops force for rocking the bell crank armature '52clockwise (FIG. 6) against the resistance of spring 53; the vertical armof the armature strikes the confronting latch 39 and rocks it to tripthe toggle for restoration by associated spring 42.

The toggle in either pole when tripped causes tripping of the toggle inthe other pole through an insulating bridge 54 which, as may beunderstood from FIG. 5, has a dual inverted U-form, one U part beingbehind the vertical arm of one armature 52 and the other U part beinglocated behind the vertical arm of the other armature. The ends of thebridge 54 are seated at the bottom of notches 55 in the side wallsections of the casing base 10b. The middle part of the bridge, that is,the connecting part between its U sections, rests on the blunt bottom ofa half V-form notch 56 (see FIG. 10) in the base section of the interiorwall of the casing, whereby the bridge may tilt forwardly. Normally, thebridge is held back by the 'armatures under the influence of theirsprings 53. A thin, insertable insulating member 57 fits at the bottomin a notch 58 in the base section of wall 10c and extends with clearanceover the middle part of the bridge 54 to keep it down. The upper edge ofthe member 57 is arcuately concave to fit to the middle section of thecam drum 20 which may be provided with lugs (not shown) to steady themember at the top against lateral shifting. Member 57 also serves as asupplementary insulator between the poles in addition to serving to keepthe bridge in place in the notches 55 and 56. Riveted to the bridge arefingers 59 which extend forwardly into confrontation with projectingends of the pivot pins 37 between the respective first and second links35 and 36 of the two toggles. When the toggle in either pole is tripped,the first and second links of the toggle buckle and their pivot pin 37snaps forwardly and strikes the confronting finger 59. This results inrocking of the bridge 54 to actuate the armature 52 of the other polefor striking the latch 39 of the toggle in the latter pole, therebytripping this toggle.

The winding 51 of each trip magnet is in series with the movable contactarm 13a of the same pole side through a pigtail connection 60. For theillustrative circuit breaker, each winding 51 consists of two turns of athick copper bar 61. The bars 61 of the respective poles are permanentlysecured to the vertical legs of thick copper angle bars 62 and 63 havingtheir horizontal legs resting on the floor of the casing base b. Theinterior longitudinal casing wall 100, which separates the two polesides, may be considered as terminating in a corner post 64 which is adistance away from the extreme tail end of the casing. As formed, thecasing has a pair of walls 65 and 66 integrally joined with the post 64,the wall 65 being in effect a continuation of the wall 10c andterminating at the extreme tail end of the casing, the other wall 66being at a right angle to the wall 65 and terminating at a side of thecasing. The walls 65 and 66 are recessed at the vertex of the cornerangle between them so as to join the corner post 64 along thinned lineswhich constitute pre-weakened lines of joinder to facilitate breakingaway of either wall from the casing. In FIGS. 3 and 7, the wall 65 isshown dot-dash to indicate that this wall has been broken away. Theangle bar 63 is at one side of the dividing wall 100 and its horizontalleg reaches substantially to the transverse wall 66. The other angle bar62 is at the opposite side of the dividing wall and has a longerhorizontal leg which reaches substantially to the tail end of the casing10.

Seated on the horizontal portion of the angle bar 63 is a wire connector67. A similar connector 68 is seated on that portion of the angle bar 62which extends between the corner post 64 and the tail end of the circuitbreaker. The connectors, comprising rectangular blocks, are mounted onthe bars by screws 69 which enable the connectors to be fixed inposition either with line-receiving openings 70 disposed longitudinallyor transversely of the casing 10. FIGS. 3 and '3 premise a situation inwhich the circuit breaker is mounted in a load center which has a pairof parallel main line cables, such as the opposite voltage line cablesof a 120240 power supply, running toward the side of the casing 10 towhich the transverse corner wall 66 extends. Accordingly, thelongitudinally extending corner wall 65 has been broken away and theconnectors 67 and 68 have been mounted with their openings 70 orientedtoward said side of the casing. One main line can be brought directly,through an opening 71 in said side of the casing, into the connector 67.The other line can be brought directly into the connector 68 inasmuch asthe wall 65 has been broken away. The connectors are provided with clampscrews 72 accessible, through holes in the casing cover, for turning toclamp the ends of the line cables to the connectors.

If the lines run toward the tail end of the circuit breaker, theninstead of breaking away the wall 65, the wall 66 will be broken awayand the connectors 67 and 68 will be disposed on bars 63 and 62 withtheir line-receiving openings 70 oriented toward the tail end of theeasing The tail end of the casing is formed open opposite the connector68, so that one of the main lines running toward the tail end can bebrought directly into the connector 68 to be clamped therein. With thetransverse wall 66 broken away, the other line running toward the tailend of the breaker can be brought directly into the connector 67 to beclamped therein. 1

In either case, the wall 65 or 66 left standing serve as an insulatorwall between the main lines extending into the circuit breaker.

FIGS. 11, 12 and 13 relate to a feature of the invention involvingmodification of the switch contacts in a breaker pole to insure at leasttwo-point engagement of the contacts, regardless of manufacturing orassembling inaccuracies or without the necessity of manufacturing orassembling the switch parts to strict tolerances. As indicated in FIG.11, a movable contact arm 13a, corresponding to contact ann 13a of themain embodiment, has a swivel coupling to the second toggle link 36.Aside from the example shown in FIG. 11, this coupling may take anyother suitable form which will permit sideswiveling of the contact armrelative to the link 36, an action which is not inhibited by thepin-and-slot means 40-41 (FIG. 6) which floatingly pivots the contactarm to a frame 23. Referring now to FIG. '12, the contact arm 13a has onits free end a modified contact 13' for engagement with the fixedcontact 14. Contact 13' is formed at the extremes of its width with apair of parallel n'dges 130 which constitute distinct contact surfacespreferably running the length of the movable contact. When the togglelinkage is actuated to bring the contact arm 13a down to engage thecontact 13' with the contact 14, if the contacts do not meet squarely,one of the ridges 130 will first engage the contact 14, causing thecontact arm 13a to tilt sidewise about the engaged n'dge until the otherridge 130 is also engaged with the contact 14. Thus, at least atwo-point engagement between the cooperable contacts of the breakerswitch is assured, allowing for greater tolerances in manufacture andassembly of the parts. Instead of the contact ridges being formed on themovable contact, they may be formed at the extremes of width of thefixed contact, as indicated in FIG. '13. Here, a fixed contact 14' isformed with the ridges and the coaction of these ridges with the contact13 (similar to the contact 13 of the main embodiment) carried by thefree end of the modified contact arm 13a will be the same as explainedin connection with FIG. 12 where the contact ridges (130) are on themovable contact.

While there have been described above the principles of the invention inconnection with specific apparatus, it is to be clearly understood thatthis description is made only by way of example and not as a limitationto the scope of the invention, as set forth in objects thereof, and inthe accompanying claims.

What is claimed is:

1. A two-pole circuit breaker to be connected in a load center to a pairof voltage lines, line-to-pole; comprising an insulating casing mountingtherein the two poles sideby-side, a first of the poles terminatingcloser to one end of the casing than the second pole; the terminalportions of the first and second poles respectively being provided withfirst and second line connectors, the first connector being accessiblethrough an opening in said casing end and the second connector beingaccessible through an opening in a side of the casting, the casing beingformed in the corner between the connectors with first and second wallssubstantially at 'a right angle to each other, the first wall blockingaccess to the first connector from said casing side and the second wallblocking access to the second connector from said casing end, the twowalls being formed with pre-weakened, breakage lines to facilitatebreaking away of either wall, the first wall being broken away to enablethe pair of voltage lines to be brought to said connectors from saidcasing side, the second wall then serving as an insulator between thevoltage lines, the second wall being alternatively broken away to enablethe voltage lines to be brought to the connectors from said casing endand the first wall then serving as an insulator between the voltagelines.

2. A two-pole circuit breaker to be connected in a load center to a pairof generally parallel and stiff voltage cable lines, pole-to-line; thecircuit breaker comprising an insulating casing mounting therein the twopoles side-by- 7 side and having an interior Wall extending between'andseparating the two poles, a first of the polesterrninating closer to oneend of the casing than the second of the poles, the terminal portionsof: the first and second poles respectively being provided with firstand second line connectors, the first connector being accessible throughan opening in said casing end and the second connector being accessiblethrough an opening in a side of the casing,-said interior wallterminating in a corner post between the two connectors, thecasing-being formed in the corner between the connectors with first andsecond corner walls extending substantially n'ght angularly to eachother from said corner post, the first wall blocking access to the firstconnector from said casing side and the second wall blocking access tothe second connector from said casing end, the two corner walls joiningthe corner post integrally along pre-weakened lines to facilitatebreaking away of either wall, the first corner wall being'broken away toenable a pair of such'voltage lines running toward'said casing side tobe brought with substantially no change in direction to the first andsecond connectors, one line to each connector, the second corner wallthen serving as an insulator between the lines, the second corner wallbeing alternatively broken away to enable a pair of such voltage lineswhen running toward said casing end to be brought with substantially nochange in direction to the first and second connectors, one line to eachconnector, and the first corner wall then serving as aninsulator'between the lines.

3. A circuit breaker as in claim 2, each said connector having anopening therein for reception of a line cable,

2,225,791 12/1940 Nau et al. 200-468 ROBERT K. SCHAEFER, PrimaryExaminer.

H. O. JONES, Assistant Examiner.

